564 research outputs found

    Alimentação de duas espécies do gênero Pseudoplatystoma do Rio Negro, Pantanal da Nhecolândia, MS, Brasil.

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    Este trabalho investigou a dieta e reprodução de duas espécies de peixes Siluriformes migradores do rio Negro, Pantanal da Nhecolândia, sob a influência do pulso de inundação. As amostras foram realizadas com o uso de redes de espera e tarrafas com diversas malhagens. De cada exemplar capturado foram obtidas as seguintes informações: comprimento total, comprimento padrão, peso total, grau de repleção e peso estomacal. Para estudo de sobreposição alimentar foi utilizado o índice de Morisita-Horn e para o estudo da dieta o Índice Alimentar. Foram capturados 225 exemplares da espécie Pseudoplatystoma corruscans (Pintado) e 85 da espécie Pseudoplatystoma reticulatum (Cachara). Destes, foram obtidos 58 estômagos com algum conteúdo. Ambas as espécies intensificaram a tomada de alimento após o período de inundação e apresentaram consumo diferenciado de recursos alimentares, com sobreposições alimentares quase inexistentes. O Índice Alimentar demonstrou uma diferenciação bastante clara nas dietas destes dois peixes piscívoros, demonstrando através de suas presas que ambas convivem explorando os recursos por meio de comportamentos distintos. This study investigated the diet and reproduction of two species of Siluriforms fish, migrating from Negro river, Pantanal of Nhecolandia, under the influence of the inundation pulse. The samples were obtained using gill net and casting seine with different screen sizes. The following informations were obtained form each specimen: total and standard length, total weight, gut fullness and stomachic weight. The Morisita-Horn index was used to study the food overlap and the food index for diet. A total of 225 specimens of Pseudoplatystoma corruscans (Pintado) and 85 of Pseudoplatystoma reticulatum (Cachara) species were captured. From these samples, 58 stomachs had some content. Both species intensified the taking of food after the inundation period and presented differentiated consumption of food resources, with very low frequency of food overlap. The food index demonstrated a great differentiation in the diets of these two predators species, showing by their preys that both live exploiting the resources by distinct behaviours

    A common neural substrate for processing scenes and egomotion-compatible visual motion

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    Neuroimaging studies have revealed two separate classes of category-selective regions specialized in optic flow (egomotion-compatible) processing and in scene/place perception. Despite the importance of both optic flow and scene/place recognition to estimate changes in position and orientation within the environment during self-motion, the possible functional link between egomotion- and scene-selective regions has not yet been established. Here we reanalyzed functional magnetic resonance images from a large sample of participants performing two well-known “localizer” fMRI experiments, consisting in passive viewing of navigationally relevant stimuli such as buildings and places (scene/place stimulus) and coherently moving fields of dots simulating the visual stimulation during self-motion (flow fields). After interrogating the egomotion-selective areas with respect to the scene/place stimulus and the scene-selective areas with respect to flow fields, we found that the egomotion-selective areas V6+ and pIPS/V3A responded bilaterally more to scenes/places compared to faces, and all the scene-selective areas (parahippocampal place area or PPA, retrosplenial complex or RSC, and occipital place area or OPA) responded more to egomotion-compatible optic flow compared to random motion. The conjunction analysis between scene/place and flow field stimuli revealed that the most important focus of common activation was found in the dorsolateral parieto-occipital cortex, spanning the scene-selective OPA and the egomotion-selective pIPS/V3A. Individual inspection of the relative locations of these two regions revealed a partial overlap and a similar response profile to an independent low-level visual motion stimulus, suggesting that OPA and pIPS/V3A may be part of a unique motion-selective complex specialized in encoding both egomotion- and scene-relevant information, likely for the control of navigation in a structured environment

    An Overview of Flow Features and Mixing in Micro T and Arrow Mixers

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    An overview of the mixing performances of micro T mixers operating with a single fluid is presented. The focus is on the relationship between the flow features and mixing. Indeed, T mixers are characterized by a variety of regimes for increasing Reynolds numbers; they are briefly described, in particular in terms of the three-dimensional vorticity field, which can explain the different mixing performances. The effects of changes in the aspect ratio of the channels are also reviewed. The role of instability and sensitivity analyses in highlighting the mechanisms of the onsets of the different regimes is then described. These analyses also suggest possible geometrical modifications to promote mixing. We focus on that consisting of the downward tilting of the inlet channels (arrow mixers). Arrow mixers are interesting because the onset of the engulfment regime is anticipated at lower Reynolds numbers. Hence, the mixing performances of arrow mixers with varying Reynolds number are described

    Genome Sequence Announcement of Lactobacillus vaginalis S-26419, Isolated from a Healthy Woman

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    The Lactobacillus vaginalis LMG S-26419 strain, also named CBA-L88 (BV2), was isolated at the AAT-Advanced Analytical Technologies laboratories from a vaginal swab obtained from a healthy woman. The total genome size is 1,806,242\u2009bp with a G+C content of 40.6%

    Jania adhaerens Primes Tomato Seed against Soil-Borne Pathogens

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    Managing soil-borne pathogens is complex due to the restriction of the most effective synthetic fungicides for soil treatment. In this study, we showed that seed priming with Jania adhaerens water-soluble polysaccharides (JA WSPs) was successful in protecting tomato plants from the soil-borne pathogens Rhizoctonia solani, Pythium ultimum, and Fusarium oxysporum under greenhouse conditions. WSPs were extracted from dry thallus by autoclave-assisted method, and the main functional groups were characterized by using FT-IR spectroscopy. WSPs were applied by seed treatment at 0.3, 0.6 and 1.2 mg/mL doses, and each pathogen was inoculated singly in a growing substrate before seeding/transplant. Overall, WSPs increased seedling emergence, reduced disease severity and increased plant development depending on the dose. Transcriptional expression of genes related to phenylpropanoid, chlorogenic acid, SAR and ISR pathways, and chitinase and beta-1,3 glucanase activities were investigated. Among the studied genes, HQT, HCT, and PR1 were significantly upregulated depending on the dose, while all doses increased PAL and PR2 expression as well as beta-1,3 glucanase activity. These results demonstrated that, besides their plant growth promotion activity, JA WSPs may play a protective role in triggering plant defense responses potentially correlated to disease control against soil-borne pathogens

    Beam-based characterization of plasma density in a capillary-discharge waveguide

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    Next-generation plasma-based accelerators can push electron bunches to gigaelectronvolt energies within centimeter distances. In these devices, the accelerating force is provided by a driver pulse, either a laser pulse or a particle bunch, that loses its energy into the plasma generating huge electric fields up to tens of GV/m. The stability of such fields strongly depends on plasma density, whose exact value should be precisely known and controlled. However, currently available methods based on spectroscopic or interferometric techniques find it very difficult to measure plasma density lower than 1015–16 cm−3 in capillary-discharge waveguides. Here, we present a novel diagnostic tool that allows us to estimate the average density of a plasma capillary by probing it with an ultra-relativistic electron beam. The plasma density and the generated accelerating field are inferred by analyzing the beam longitudinal phase space after its interaction with the plasma. The results are validated by simulations showing excellent agreement

    Mixing Improvement in a T-Shaped Micro-Junction through Small Rectangular Cavities

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    The T-shaped micro-junction is among the most used geometry in microfluidic applications, and many design modifications of the channel walls have been proposed to enhance mixing. In this work, we investigate through numerical simulations the introduction of one pair of small rectangular cavities in the lateral walls of the mixing channel just downstream of the confluence region. The aim is to preserve the simple geometry that has contributed to spread the practical use of the T-shaped micro-junction while suggesting a modification that should, in principle, work jointly with the vortical structures present in the mixing channel, further enhancing their efficiency in mixing without significant additional pressure drops. The performance is analyzed in the different flow regimes occurring by increasing the Reynolds number. The cavities are effective in the two highly-mixed flow regimes, viz., the steady engulfment and the periodic asymmetric regimes. This presence does not interfere with the formation of the vortical structures that promote mixing by convection in these two regimes, but it further enhances the mixing of the inlet streams in the near-wall region of the mixing channel without any additional cost, leading to better performance than the classical configuration

    Sustainable exploitation of residual cynara cardunculus l. To levulinic acid and n-butyl levulinate

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    Hydrolysis and butanolysis of lignocellulosic biomass are efficient routes to produce two valuable bio-based platform chemicals, levulinic acid and n-butyl levulinate, which find increasing applications in the field of biofuels and for the synthesis of intermediates for chemical and pharmaceutical industries, food additives, surfactants, solvents and polymers. In this research, the ac-id-catalyzed hydrolysis of the waste residue of Cynara cardunculus L. (cardoon), remaining after seed removal for oil exploitation, was investigated. The cardoon residue was employed as-received and after a steam-explosion treatment which causes an enrichment in cellulose. The effects of the main reaction parameters, such as catalyst type and loading, reaction time, temperature and heat-ing methodology, on the hydrolysis process were assessed. Levulinic acid molar yields up to about 50 mol % with levulinic acid concentrations of 62.1 g/L were reached. Moreover, the one-pot bu-tanolysis of the steam-exploded cardoon with the bio-alcohol n-butanol was investigated, demon-strating the direct production of n-butyl levulinate with good yield, up to 42.5 mol %. These results demonstrate that such residual biomass represent a promising feedstock for the sustainable production of levulinic acid and n-butyl levulinate, opening the way to the complete exploitation of this crop
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